i like this way because you don't need to create two components just one.
.checkmark:after {
opacity: 1;
height: 4em;
width: 2em;
-webkit-transform-origin: left top;
transform-origin: left top;
border-right: 2px solid #5cb85c;
border-top: 2px solid #5cb85c;
content: '';
left: 2em;
top: 4em;
position: absolute;
}